[all] Code cleanup before v2 release

[gadicc]

For all packages:

• Look at commented out code and remove if we're sure it's no longer needed
• Clean up Session variables, div IDs, etc.
• Look/assess all XXX and TODO comments (convert to issues)
• Verify package.js requirements that they're still all needed
• Linter configuration file, CONTRIBUTORS file.

[MartinFournier]

I'd also suggest adding eslint or some other linter configuration file. It would help contributors respect the same coding style.

[gadicc]

Right you are, added.